Molecular differentiation of null alleles at ZCCT-1 genes on the A, B, and D genomes of hexaploid wheat

• Published in: Molecular breeding 2011-04, Vol.27 (4), p.501-510
• Main Authors: Zhu, Xinkai, Tan, ChorTee, Cao, Shuanghe, Yan, Liuling
• Format: Article
• Language: English
• Subjects: Acrylamide; Alleles; Amino acids; Biomedical and Life Sciences; Biotechnology; Cultivars; Electrophoresis; Gene deletion; Genes; Genetics; Genomes; Genomics; growth habit; Life Sciences; Molecular biology; Natural mutants; Plant biology; Plant breeding; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant Sciences; Polyploidy genomes; Proteins; Triticum aestivum; Triticum monococcum; Vernalization; VRN-2 genes; Wheat; Wheat genome evolution; Zinc finger proteins
• ISSN: 1380-3743; 1572-9788
• DOI: 10.1007/s11032-010-9447-8

A dominant allele of the vernalization gene Vrn-2 is the wild type conferring winter growth habit, whereas a recessive vrn-2 allele confers spring growth habit. The recessive vrn-2 allele is mutated due to the deletion of the complete gene (a null form) or alternation of a key amino acid in the VRN-2 protein (a nonfunctional form) in diploid wheat or tetraploid wheat. VRN-2 is also denoted ZCCT due to the presence of a zinc finger and a CCT domain in its protein. There are two paralogous ZCCT genes at the VRN-2 locus in diploid Triticum monococcum and three paralogous ZCCT genes on each of the A and B genomes in tetraploid wheat, but little is known about the allelic variation in VRN-2 in hexaploid wheat. In the study reported here, we performed a one-shot PCR to simultaneously amplify the promoter regions of the three ZCCT-1 genes from hexaploid wheat, including the 302-bp fragment from ZCCT-A1, the 294-bp fragment from ZCCT-B1, and the 320-bp fragment from ZCCT-D1. Each amplicon could be differentiated by electrophoresis in an acrylamide/bisacrylamide gel. This PCR marker for different lengths of the three ZCCT-1 genes was used to search for null alleles in hexaploid wheat. A null allele was found in each of ZCCT-A1, ZCCT-B1, and ZCCT-D1 among 74 cultivars and genetic stocks of U.S. hexaploid wheat. Among 54 Chinese wheat cultivars, breeding lines, and landraces, we identified three accessions carrying a single null allele at ZCCT-A1, three accessions carrying a null allele at ZCCT-B1, and one accession carrying a double null allele at both ZCCT-A1 and ZCCT-D1. The potential application of these natural ZCCT-1 mutant materials in wheat breeding programs and studies on the genetics of wheat is discussed.